WTPA43 PHFO 190905
TCDCP3
TROPICAL DEPRESSION TWO-C DISCUSSION NUMBER 2
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP022006
1100 PM HST MON SEP 18 2006
TROPICAL DEPRESSION TWO-C CONTINUES TO STRENGTHEN AS IT MOVES
WESTWARD WELL SOUTH OF THE HAWAIIAN ISLANDS. OVER THE PAST SIX
HOURS...TWO-C HAS STARTED TO SHOW SIGNS OF BETTER ORGANIZATION AND
CONVECTION NEAR THE CENTER HAS INCREASED. CLOUD COVER ASSOCIATED
WITH THE INCREASE IN CONVECTION HAS ALSO MADE IT MORE DIFFICULT TO
LOCATE THE EXACT CENTER. THE MAXIMUM WIND SPEED WAS INCREASED TO 30
KNOTS BASED ON AGENCY FIXES OF 1.5 AND QUIKSCAT DATA. WINDSAT DATA
AT 0416 UTC DID INDICATE SOME 40 KNOT WINDS NORTH OF THE CENTER NEAR
10.5N LATITUDE...BUT THESE SEEMED UNREASONABLE AND WERE DISCOUNTED.
THE FORECAST TRACK OF TWO-C HAS BEEN ADJUSTED SOUTHWARD OR TO THE
LEFT OF THE PREVIOUS TRACK...WHICH RELIED EXCLUSIVELY ON THE BETA
ADVECTION AND PERSISTENCE/CLIMATOLOGY MODELS. THE CURRENT GUIDANCE
SUITE...INCLUDING GFDL...GFS...UKMET...AND CONU FORECASTS...SHOWS A
CONSIDERABLE SHIFT TOWARD THE SOUTH BEYOND 36 HOURS...TAKING TWO-C
ON A MORE WESTWARD TRACK. DEEP LAYER MEAN WINDS THAT WOULD HELP TO
STEER THIS STORM ARE EXPECTED TO REMAIN ALMOST FROM DUE EAST...WHICH
ADDS CREDENCE TO THE MORE WESTWARD MOVEMENT. THE CURRENT FORECAST
TRACK REMAINS CLOSE TO THE PREVIOUS TRACK THROUGH 36 HOURS AND
SHIFTS CLOSER TO THE GFDL TRACK THEREAFTER...WHICH IS NOT QUITE AS
FAR SOUTH AS THE CONU.
WIND RADII WERE ALSO EXPANDED PRIMARILY THROUGH 36 HOURS IN RESPONSE
TO THE INCREASED IN INTENSITY AND QUIKSCAT DATA. WIND RADII REMAIN
LARGEST IN THE NORTHEAST QUADRANT OF THE STORM...WHERE THE GRADIENT
BETWEEN THE STORM AND HIGH PRESSURE TO THE NORTHEAST IS THE
STRONGEST.
THE FORECAST INTENSITY WAS INCREASED THROUGH 36 HOURS IN RESPONSE TO
THE INCREASE IN INITIAL INTENSITY. THERE IS VERY LITTLE SHEAR NEAR
TWO-C AT THE MOMENT AND MODELS ARE IN GOOD AGREEMENT THAT TWO-C WILL
ENCOUNTER LITTLE TO NO VERTICAL SHEAR OVER THE NEXT SEVERAL DAYS.
EXPERIMENTAL VERTICAL SHEAR ESTIMATES FROM UW-CIMMS CONCUR...AND
LIST DEVELOPMENT OUTLOOK AS VERY FAVORABLE IN THE NEAR TERM. TWO-C
IS SPINNING OVER SSTS OF 28 DEGREES CELSIUS AND GIVEN ITS FORECAST
TRACK WILL REMAIN OVER WATER NEAR 28 DEGREES CELSIUS. ALL SIGNS
THEREFORE...ARE FAVORABLE FOR ADDITIONAL DEVELOPMENT. AS IT
STANDS...TWO-C IS EXPECTED TO BECOME A TROPICAL STORM EARLY
TUESDAY...AND REACH HURRICANE STRENGTH WEDNESDAY.
ITS PROJECTED PATH THROUGH 120 HOURS KEEPS TWO-C OVER WATER AND AWAY
FROM ANY MAJOR PACIFIC ISLANDS. THE SOUTHWARD ADJUSTMENT OF THE
FORECAST TRACK AFTER 36 HOURS ALSO PLACES TWO-C FURTHER AWAY FROM
JOHNSTON ISLAND.
FORECAST POSITIONS AND MAX WINDS
INITIAL 19/0900Z 10.0N 158.1W 30 KT
12HR VT 19/1800Z 10.3N 159.8W 40 KT
24HR VT 20/0600Z 10.8N 162.0W 45 KT
36HR VT 20/1800Z 11.4N 164.2W 55 KT
48HR VT 21/0600Z 12.0N 166.5W 65 KT
72HR VT 22/0600Z 13.4N 171.1W 75 KT
96HR VT 23/0600Z 14.4N 174.3W 80 KT
120HR VT 24/0600Z 14.8N 176.5W 80 KT
$$
FORECASTER TANABE/HOUSTON